The use of magnetic pulse technologies in forming and joining components has been known for years. The widespread use of magnetic pulse forming and joining has been generally limited to use with tubular workpieces of relatively simple geometries. Traditionally, magnetic pulse forming and joining has been accomplished through the use of a closed coil configured such that the parts to be formed or joined can be slid into and out of the coil. Such closed coils have not allowed the application of magnetic pulse technologies to workpieces having anything other than simple shapes.
To overcome the limitations inherent in closed coils, numerous split concentrators have been developed to provide additional flexibility to closed coil devices. Such split concentrator designs are found in U.S. Pat. Nos. 3,486,356, 3,412,590, 3,391,558, and 3,252,313, just to name a few. Still, use of a split concentrator with a closed coil device does not provide the flexibility needed in many situations; after all the formed or welded workpiece must still be able to slide out of the coil.
Others have essentially cut a closed coil device in half so that it can be opened to insert and remove workpieces, yet still create a closed coil when the halves are brought together. Such configurations have been plagued by sparking along the interface between the two sections which leads to premature wear and failure of the coil. Yet another problem plaguing magnetic pulse technology systems has been the lack of control of the current as it passes through the sections. Prior art systems have failed to recognize the importance that the electrical characteristics of the entire system have on the current flow within the sections. A magnetic pulse technology power source may be tens of feet away from the actual forming or joining device. The power transmission systems responsible to transmitting hundreds of thousands of amperes at an electrical potential of thousands of volts are generally the source of several problems. Large power transmission circuits operating at the frequencies used in magnetic pulse forming and joining, generally tens of kHz, produce large inductance loads which negatively impact the operation.
Reducing the inductance in magnetic pulse technology systems is very important for two reasons. First, high inductance in a magnetic pulse system has the effect of reducing the magnitude of the current, which consequently reduces the magnitude of the electromagnetic pulse force. Therefore, by reducing the inductance in a magnetic pulse system, the electromagnetic pulse force can be increased without making any changes to the magnetic pulse power supply, thereby improving the forming or joining of the workpiece(s). Secondly, high inductance in a magnetic pulse system has the effect of reducing the current frequency in the system, which consequently increases the rise time of the magnetic pulse force, which is particularly important in magnetic pulse welding. Therefore, by reducing the inductance in a magnetic pulse system, particularly in the conductors, the rise time of the magnetic pulse force can be reduced, again, without making any changes to the magnetic pulse power supply. Prior magnetic pulse technology systems have not been designed with reduction of inductance of the conductors, and all the associated benefits, in mind. The present system addresses this need.
The field of magnetic pulse forming and welding has needed a design in which multiple individual components can be easily configured around a workpiece in such a manner that each component constitutes a separate electrical circuit, yet when properly installed and operated, the individual components work together to produce the same effect as a single closed coil. While some of the prior art devices attempted to improve the state of the art, none has achieved the unique and novel configurations and capabilities of the present invention. With these capabilities taken into consideration, the instant invention addresses many of the shortcomings of the prior art and offers significant benefits heretofore unavailable.